Treatment of Radioactive Waste Streams at
the Idaho Chemical Processing Plant by
Evaporation and Ion Exchange
D. W. RHODES, Group Leader
Waste Management, Chemistry
G. E. LOHSE, Group Leader
Waste Management, Engineering
Idaho Nuclear Corporation
Chemical Programs Division
Idaho Falls, Idaho
INTRODUCTION
The Idaho Chemical Processing Plant (ICPP) is an AEC-owned facility operated
by Idaho Nuclear Corporation at the National Reactor Testing Station (NRTS) for
the recovery of fissile materials, principally U-235. This facility is located about 50
miles west of Idaho Falls, Idaho. The irradiated fuels are prepared for solvent
extraction of the uranium by several methods, including a) dissolution in mineral
acids (nitric, sulfuric, and hydrofluoric); b) electrolytic dissolution in nitric acid; and
c) in the near future, dissolution of ash (following burning of combustible fuel in a
fluidized bed burner) with mineral acids. During the fuel reprocessing, high- and
intermediate-level radioactive wastes containing greater than 99 percent of the fission
products, and low-level wastes containing only a fraction of 1 percent of the fission
products are generated. The high-level wastes are stored for an interim period in
cooled 300,000 gallon stainless steel tanks (Type 316 ELC, 304L, and 348)
contained within buried concrete vaults. Eventually, these wastes are converted to a
granular solid by fluidized bed calcination, and stored in stainless steel bins which are
also contained in buried concrete vaults (1). Using this technique, nearly all of the
radionuclides eventually are stored as a part of the granular solids.
The low-and intermediate-level wastes containing small quantities of
radionuclides are processed to minimize the volume of waste that has to be stored,
and also to reduce to the lowest practicable level, the amount of radionuclides
released to the environment. The intent of this report is to describe the system and
methods used for treating these low- and intermediate-level wastes at the ICPP.
WASTE COLLECTION AND TREATMENT
All of the potentially radioactive waste generated at the ICPP, except the
high-level waste, is received in an evaporator waste collection tank. This amounts to
about 1,200,000 gallons of liquid waste annually and includes waste from laboratory
sinks and safety shower drains, cooling water from a uranium product denitrator,
process sampler drains, cell floor drains, equipment decontamination, and some
wastes from the test reactor areas at the NRTS. A simplified schematic diagram of
the liquid waste collection system at the ICPP is shown in Figure 1.
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